title: Evaluation of expanded polytetrafluoroethylene-covered stents for the treatment of venous outflow stenosis in hemodialysis access grafts.
abstract: OBJECTIVE
  To investigate the use of an expanded polytetrafluoroethylene-coated nitinol stent-graft in patients with failing hemodialysis access circuits and compare grafts with and without a heparin-coated surface.
  
  
  METHODS
  A single-institution retrospective review of 16 patients (average age, 55 years; seven men) treated for hemodialysis access circuit stenoses was performed. Patients had a prosthetic arteriovenous (AV) graft (n = 10) or autogenous AV fistula (n = 6), all with clinically relevant access stenoses that were refractory to angioplasty alone; 10 patients also had access circuit thrombosis at the time of treatment. Stents were placed in the basilic (n = 4), brachial (n = 7), cephalic (n = 4), and femoral (n = 1) veins. Study endpoints included primary treatment area patency, primary circuit patency, primary assisted circuit patency, and secondary circuit patency, followed to a maximum of 6 months.
  
  
  RESULTS
  Primary treatment area patency rates at 30 days and 180 days were 75% and 31%, respectively. Secondary patency rates at the same time points were 88% and 68%, respectively. Mean primary treatment area patency was 93 days. Thrombosis was a major cause of failure, occurring in seven of 11 cases of primary treatment area patency loss. Subgroup analysis demonstrated that the heparin-coated configuration (n = 7) showed a 6-month primary patency rate of 57%, compared with 11% for the stent-grafts without heparin bonding (n = 9; P = .06).
  
  
  CONCLUSIONS
  Overall, the majority of deployed stent-grafts lost primary patency within 6 months, with thrombosis a major cause of failure. However, the addition of a heparin-coated surface appeared to improve results in these otherwise treatment-refractory access circuits.
authors.affiliation: Department of Radiology, University of California Los Angeles, 10833 LeConte Ave., Mail Code CHS 172115, Los Angeles, CA 90095, USA.
authors.forename: Michael G
authors.initials: MG
authors.lastname: Chan
authors.forename: Frank J
authors.initials: FJ
authors.lastname: Miller
authors.forename: Karim
authors.initials: K
authors.lastname: Valji
authors.forename: Michael D
authors.initials: MD
authors.lastname: Kuo
mesh_terms: D000328:Adult; D000368:Aged; D000497:Alloys; D017130:Angioplasty / Q000295:instrumentation*; D000925:Anticoagulants / Q000008:administration & dosage; D001166:Arteriovenous Shunt, Surgical / Q000009:adverse effects; D001807:Blood Vessel Prosthesis; D019917:Blood Vessel Prosthesis Implantation / Q000009:adverse effects / Q000295:instrumentation*; D020099:Coated Materials, Biocompatible; D003251:Constriction, Pathologic; D005260:Female; D006083:Graft Occlusion, Vascular / Q000209:etiology / Q000503:physiopathology / Q000628:therapy*; D006493:Heparin / Q000008:administration & dosage; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D011138:Polytetrafluoroethylene; D011474:Prosthesis Design; D006435:Renal Dialysis; D012189:Retrospective Studies; D055502:Secondary Prevention; D015607:Stents; D013997:Time Factors; D016896:Treatment Outcome; D014654:Vascular Patency; D020246:Venous Thrombosis / Q000209:etiology / Q000517:prevention & control
chemical_list: D000497:Alloys; D000925:Anticoagulants; D020099:Coated Materials, Biocompatible; C013616:nitinol; D011138:Polytetrafluoroethylene; D006493:Heparin